Google has started rolling out Android 6.0 Marshmallow update to affordable Android One smartphones. The same update was debuted on Google Nexus devices earlier this week.

It is rolling out as an over-the-air (OTA) update. Although it is initially available for select Android One smartphones in India, including the Micromax Canvas A1, Karbonn Sparkle V and Spice Dream Uno, it would soon arrive for all Android One devices and across all geographical regions in the coming future.

Google is sending out push notifications on compatible Android One devices. You can manually check the update availability by going to Settings > About phone > Software update. The update is about 338MB in size, and you need to have a high-speed data or Wi-Fi connection on your Android One device to smoothly download the entire update package.

The update does not come with a complete changelog but a note reveals that it brings an upgrade to Android 6.0 Marshmallow, which was officially released earlier this year. "This software update will upgrade your Android One to Android 6.0, Marshmallow, which delivers major improvements to the functionality and performance of your device," the note reads.

It includes new features such as 'Google Now on Tap' to deliver enhanced search experience, 'Doze' to automatically put the device into a sleep state and 'App Standby' to limit the impact of standby apps. It also comes with improvements like improved app permissions. However, Google has not provided fingerprint sensor support and Android Pay integration on the update package for Android One devices as both the features are specifically designed for high-end devices.

Apart from Google, Sony, HTC and Motorola have recently announced plans to release Android 6.0 Marshmallow update for their devices. LG has also joined the group by listing the update on its official site in South Korea.